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41.
Guillermo Vinué Amelia Simó Sandra Alemany 《Advances in Data Analysis and Classification》2016,10(1):103-132
Clustering of objects according to shapes is of key importance in many scientific fields. In this paper we focus on the case where the shape of an object is represented by a configuration matrix of landmarks. It is well known that this shape space has a finite-dimensional Riemannian manifold structure (non-Euclidean) which makes it difficult to work with. Papers about clustering on this space are scarce in the literature. The basic foundation of the \(k\)-means algorithm is the fact that the sample mean is the value that minimizes the Euclidean distance from each point to the centroid of the cluster to which it belongs, so, our idea is integrating the Procrustes type distances and Procrustes mean into the \(k\)-means algorithm to adapt it to the shape analysis context. As far as we know, there have been just two attempts in that way. In this paper we propose to adapt the classical \(k\)-means Lloyd algorithm to the context of Shape Analysis, focusing on the three dimensional case. We present a study comparing its performance with the Hartigan-Wong \(k\)-means algorithm, one that was previously adapted to the field of Statistical Shape Analysis. We demonstrate the better performance of the Lloyd version and, finally, we propose to add a trimmed procedure. We apply both to a 3D database obtained from an anthropometric survey of the Spanish female population conducted in this country in 2006. The algorithms presented in this paper are available in the Anthropometry R package, whose most current version is always available from the Comprehensive R Archive Network. 相似文献
42.
Amelia Bilbao-Terol Mariano Jiménez Mar Arenas-Parra 《Annals of Operations Research》2016,245(1-2):137-162
In this paper a multi-criteria group decision making model is presented in which there is a heterogeneity among the decision makers due to their different expertise and/or their different level of political control. The relative importance of the decision makers in the group is handled in a soft manner using fuzzy relations. We suppose that each decision maker has his/her preferred solution, obtained by applying any of the techniques of distance-based multi-objective programming [compromise, goal programming (GP), goal programming with fuzzy hierarchy, etc.]. These solutions are used as aspiration levels in a group GP model in which the differences between the unwanted deviations are interpreted in terms of the degree of achievement of the relative importance amongst the group members. In this way, a group GP model with fuzzy hierarchy (Group-GPFH) is constructed. The solution for this model is proposed as a collective decision. To show the applicability of our proposal, a regional forest planning problem is addressed. The objective is to determine tree species composition in order to improve the values achieved by Pan-European indicators for sustainable forest management. This problem involves stakeholders with competing interests and different preference schemes for the aforementioned indicators. The application of our proposal to this problem allows us to be able to comfortably address all these issues. The results obtained are consistent with the preferences of each stakeholder and their hierarchy within the group. 相似文献
43.
Amelia Bilbao-Terol Mar Arenas-Parra Verónica Cañal-Fernández Celia Bilbao-Terol 《Annals of Operations Research》2016,247(2):549-580
The current economic crisis fuels the financial social responsibility after an epoch of many excesses with damaging effects. This work tackles two emerging streams in the financial literature: the behavioral portfolio theory with mental accounting and the socially responsible investment (SRI). Promoting SRI is regarded by a lot of financial experts, policymakers and researchers from the field of economic and social sciences, as one of the potential solutions in order to avoid future crises. Therefore, new models for this investment approach are necessary. We try to support the class of investors that select their investments under a mental accounting framework and also they want to achieve a certain level of SR quality in their portfolios. In order to reconcile the two choice frames, avoiding unnecessary sacrifices in financial performance, we have designed a model based on goal programming that integrates the two cornerstones of the investor. Furthermore, we propose a fuzzy inference system to determine the amount of money allocated to each mental account as well as the confidence level assigned to each mental account. This tool is based on expert knowledge modeled by fuzzy if–then rules. 相似文献
44.
Teso Vilar E García Fraile A de la Moya Cerero S Martínez-Ruiz P Moreno Jiménez F 《Rapid communications in mass spectrometry : RCM》2011,25(3):395-409
The electron ionization (EI) mass spectra of a series of bridgehead-substituted 3,3-dimethylnorbornan-2-ones, derived from natural (1R)-(+)-camphor, have been studied and their cleavage mechanisms rationalized on the basis of the substituent shifts as well as on the identification of relevant peaks through accurate mass measurements and collision-induced dissociation (CID) tandem mass spectrometric experiments. The fragmentation patterns are very dependent on both the structural nature and the electronic properties of the bridgehead substituent. The driving force for the main fragmentation pathways are competitive cleavages of the C(1)-C(2) and C(2)-C(3) bonds directed by the bridgehead substituent and either the gem-dimethyl or carbonyl groups. These cleavages lead to distonic ions in which the charge is preferentially located either at the C(1), C(2) or C(3) positions depending on the electronic character and structural nature of the bridgehead substituent. This charge distribution determines the subsequent rearrangements and fragmentations. 相似文献
45.
Two new compounds in the Ca—Cu—Cd system of nominal composition Ca5Cu2Cd and Ca2Cu2Cd9 are synthesized from nearly stoichiometric mixtures of the elements (1100 °C, 48 h). 相似文献
46.
Ray AW Taatjes CA Welz O Osborn DL Meloni G 《The journal of physical chemistry. A》2012,116(25):6720-6730
Earlier synchrotron photoionization mass spectrometry experiments suggested a prominent ring-opening channel in the OH-initiated oxidation of cyclohexene, based on comparison of product photoionization spectra with calculated spectra of possible isomers. The present work re-examines the OH + cyclohexene reaction, measuring the isomeric products of OH-initiated oxidation of partially and fully deuterated cyclohexene. In particular, the directly measured photoionization spectrum of 2-cyclohexen-1-ol differs substantially from the previously calculated Franck-Condon envelope, and the product spectrum can be fit with no contribution from ring-opening. Measurements of H(2)O(2) photolysis in the presence of C(6)D(10) establish that the addition-elimination product incorporates the hydrogen atom from the hydroxyl radical reactant and loses a hydrogen (a D atom in this case) from the ring. Investigation of OH + cyclohexene-4,4,5,5-d(4) confirms this result and allows mass discrimination of different abstraction pathways. Products of 2-hydroxycyclohexyl-d(10) reaction with O(2) are observed upon adding a large excess of O(2) to the OH + C(6)D(10) system. 相似文献
47.
Castro-Ochoa D Peña-Montes C González-Canto A Alva-Gasca A Esquivel-Bautista R Navarro-Ocaña A Farrés A 《Applied biochemistry and biotechnology》2012,166(5):1275-1290
Cutinases are versatile carboxylic ester hydrolases with great potential in many biocatalytic processes, including biodiesel
production. Genome sequence analysis of the model organism Aspergillus nidulans reveals four genes encoding putative cutinases. In this work, we purified and identified for the first time a cutinase (ANCUT2)
produced by A. nidulans. ANCUT2 is a 29-kDa protein which consists of 255 amino acid residues. Comparison of the amino acid sequence of ANCUT2 with
other microbial cutinase sequences revealed a high degree of homology with other fungal cutinases as well as new features,
which include a serine-rich region and conserved cysteines. Cutinase production with different lipidic and carbon sources
was also explored. Enzyme activity was induced by olive oil and some triacylglycerides and fatty acids, whereas it was repressed
by glucose (1%) and other sugars. In some conditions, a 22-kDa post-translational processing product was also detected. The
cutinase nature of the enzyme was confirmed after degradation of apple cutin. 相似文献
48.
A McAnaw M Elena Lopez G Scott D Ellis D McKay GM Rosair AJ Welch 《Dalton transactions (Cambridge, England : 2003)》2012,41(36):10957-10969
Reduction of the tethered carborane 1,2-μ-(CH(2)SiMe(2)CH(2))-1,2-closo-C(2)B(10)H(10) followed by metallation with {CpCo} or {(p-cymene)Ru} fragments affords both C,C'-dimethyl 4,1,2-MC(2)B(10) and 4,1,6-MC(2)B(10) species. DFT calculations indicate that the barriers to isomerisation of both 4-Cp-4,1,2-closo-CoC(2)B(10)H(12) and 4-(η-C(6)H(6))-4,1,2-closo-RuC(2)B(10)H(12) to their respective 4,1,6-isomers are too high for this to be the origin of the unexpected formation of 4,1,6-MC(2)B(10) products (in marked contrast to the related isomerisation of 1,2-closo-C(2)B(11)H(13) to 1,6-closo-C(2)B(11)H(13)), and, indeed, the 4,1,2-species are recovered unchanged from refluxing toluene. Equally, the DFT-calculated profile for the isomerisation of [7,8-nido-C(2)B(10)H(12)](2-) to [7,9-nido-C(2)B(10)H(12)](2-) suggests that the unexpected formation of 4,1,6-metallacarboranes is unlikely to result from isomerisation of a reduced (nido) carborane following desilylation. Instead, the source of the 4,1,6-MC(2)B(10) compounds is traced to desilylation of 1,2-μ-(CH(2)SiMe(2)CH(2))-1,2-closo-C(2)B(10)H(10) by Li or Na prior to reduction. The supraicosahedral metallacarboranes 1,8-Me(2)-4-Cp-4,1,8-closo-CoC(2)B(10)H(10), 1,12-Me(2)-4-Cp-4,1,12-closo-CoC(2)B(10)H(10) and 1,12-Me(2)-4-(p-cymene)-4,1,12-closo-RuC(2)B(10)H(10) are also reported with all new species characterised both spectroscopically and crystallographically. 相似文献
49.
PC Andrews M Busse GB Deacon RL Ferrero PC Junk JG Maclellan A Vom 《Dalton transactions (Cambridge, England : 2003)》2012,41(38):11798-11806
Four new tris-substituted bismuth(iii) sulfonates of general formula [Bi(O(3)SR)(3)] (R = phenyl 1, p-tolyl 2, 2,4,6-mesityl 3 and S-(+)-10-camphoryl 4) have been synthesised and characterised. Their synthesis by solvent-free (SF) and solvent-mediated (SM) methods has been explored and their activity against Helicobacter pylori has been investigated. The compounds 1-4 display a remarkable in vitro activity against three laboratory strains of H. pylori (B128, 26?695 and 251) with minimum inhibitory concentration (MIC) values as low as 0.049 μg mL(-1) for the strains B128 and 26?695, and 0.781 μg mL(-1) for the clinical isolate 251. This places most MIC values in the nano-molar region and demonstrates the strong influence of the sulfonate group on the bactericidal properties. The novel solid state structure [Bi(8)(O(3)SMes)(20)(SO(4))(2)(H(2)O)(6)]·(C(7)H(8))(7)5·(C(7)H(8))(7), derived from the SM reaction under reflux conditions, is presented and the incorporation of the two inorganic sulfate anions in the centre of the wheel-like bismuth sulfonate cluster explained. 相似文献
50.
Amelia Carolina Sparavigna 《Phase Transitions》2013,86(8):620-631
We present a polarizing optical microscopy study of a liquid-crystal mixture of trans-4-hexylcyclohexanecarboxilic (C6) and benzoic acids. Both materials have carboxylic groups that can form dimers through hydrogen bonding. The mixture is nematic at room temperature and has the clearing point at 88°C. The nematic phase shows ringed spherulites, sometimes looking like spiral structures, and undulated textures, which remain visible when heating the sample till 71°C. This is the temperature of a texture transition inside the nematic phase. 相似文献